This invention relates to a sealed container using as a structural component a container barrel body made of paper. The sealed container is adapted to withstand internal pressure and is suitable for use as a sealed beverage container.
In recent years, from the standpoint of saving resources and the disposal of used containers, a large number of sealed containers have been used for containing fluid contents, such as a composite sealed can using a container barrel body made of paper as a structural component thereof. The sealed composite container of this type can be constructed as shown in FIG. 8, for example. As can be seen, a metallic closure a is hermetically attached to a container barrel body b made of paper by a double curling fastening similar to that used in a conventional metallic container barrel body in manufacturing canned beverages. In this case, the container barrel body made of paper lacks extensibility, unlike the metallic container barrel body, and accordingly when the same is subjected to the double curling fastening, a folded point d of a curling flange thereof and a compressed intermediate part thereof between a seaming wall part e and a chuck wall part f of the metallic closure member a are compressed to become stiff or weakened. When the internal gaseous pressure of the sealed container increases to a high level, the container barrel body made of paper is broken or ruptured at its folded point d and/or at its intermediate part. Consequently the metallic closure member sometimes comes off of the container barrel body.